"A patent pool is being assembled to go after Theora and other 'open source' codecs now," Jobs wrote in the e-mail, which Apple did not immediately confirm as authentic. "Unfortunately, just because something is open source, it doesn't mean or guarantee that it doesn't infringe on others' patents."

"The distinction between the availability of source code and the ownership of the intellectual property in that available source code is critical. Today, intellectual-property rights for H.264 are broadly available through a well-defined program managed by MPEG LA. The rights to other codecs are often less clear, as has been described in the press," Microsoft said in its blog post.

The patent saber rattling could present trouble for Mozilla and Google, which supports both h.264 and Ogg Theora in its Chrome browser and is expected in May to announce plans to open-source the VP8 codec it acquired from On2 Technologies. Opera, the other major browser company in the world that uses Ogg Theora, could also be affected by any patent offensive.

Representatives from Google did not immediately respond to a request for comment. Microsoft declined to address any pending patent moves directly, but it pointed reporters back to its Friday morning blog post.

A representative for the MPEG LA group declined to comment for this story.

Updated 2:33 p.m.: Mozilla issued the following statement: "We believe that it is in the public interest for HTML5 video to be backed by multiple, open and royalty-free codecs available in a way that is consistent with the W3C license standards. We would absolutely consider H.264 if MPEG LA would make it available under open web terms as defined by the W3C standards. We stand by our position on Theora."

Updated 3:33 p.m.: Opera released its own statement from CTO Håkon Wium Lie: ""For the open Web to thrive, all media -- including video -- must be usable without paying licensing fees for codecs. Browser vendors that truly support an open web must work to establish a license-free baseline video codec."

About the author

Tom Krazit writes about the ever-expanding world of Google, as the most prominent company on the Internet defends its search juggernaut while expanding into nearly anything it thinks possible. He has previously written about Apple, the traditional PC industry, and chip companies. E-mail Tom.
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